GPT-5 Nano vs Claude Haiku 4.5 vs Seed-OSS-36B-Instruct
GPT-5 Nano comes out ahead, 70 to 66 and 60 on our weighted score, and it is the cheaper option too.
- Our pick
OpenAIGPT-5 Nano
70/100- ECI139.3
- Price$0.05 / $0.40
- Context400K
AnthropicClaude Haiku 4.5
66/100- ECI142.2
- Price$1.00 / $5.00
- Context200K
ByteDance SeedSeed-OSS-36B-Instruct
60/100- ECI—
- Price—
- Context524K
GPT-5 Nano is our pick
GPT-5 Nano is the better all-round choice, scoring 70/100 against Claude Haiku 4.5 (66) and Seed-OSS-36B-Instruct (60). It leads on capability. Claude Haiku 4.5 wins on inputs & features. Seed-OSS-36B-Instruct wins on context window. The score weighs capability 67%, inputs & features 20%, context window 13%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because Seed-OSS-36B-Instruct has no Capabilities Index score yet.
- CapabilityGPT-5 NanoShared benchmarks: GPT-5 Nano 75.3% · Seed-OSS-36B-Instruct 69.5% · Claude Haiku 4.5 68.9%
- Lowest priceGPT-5 NanoGPT-5 Nano $0.138 · Claude Haiku 4.5 $2.00 per 1M tokens (3:1 blend) · Seed-OSS-36B-Instruct unpriced
- Longest contextSeed-OSS-36B-InstructSeed-OSS-36B-Instruct 524,288 · GPT-5 Nano 400,000 · Claude Haiku 4.5 200,000 tokens
- Widest inputsClaude Haiku 4.5GPT-5 Nano: Text, Images · Claude Haiku 4.5: Text, Images, PDFs · Seed-OSS-36B-Instruct: Text
- Self-hostingSeed-OSS-36B-InstructPublishes downloadable weights (Apache 2.0)
| Measure | Weight | GPT-5 Nano | Claude Haiku 4.5 | Seed-OSS-36B-Instruct |
|---|---|---|---|---|
| CapabilityShared benchmarks | 67% | 75 | 69 | 70 |
| Inputs & features | 20% | 70 | 80 | 35 |
| Context window | 13% | 44 | 32 | 49 |
| Overall | 100% | 70/100 | 66/100 | 60/100 |
Left out because at least one model lacks the data: price. The remaining weights were rescaled.
Every spec in one table
Highlighted cells lead their row. Dashes mean the data is not published.
| Specification | GPT-5 NanoOpenAI | Claude Haiku 4.5Anthropic | Seed-OSS-36B-InstructByteDance Seed |
|---|---|---|---|
| Capability | |||
| Capabilities Index (ECI) | 139.3 | 142.2 (best) | — |
| ECI rank | #116 of 165 | #102 of 165 (best) | — |
| GPQA DiamondGraduate-level science questions | 69.4% | 71.2% | 71.5% (best) |
| FrontierMath Tiers 1–3Research-level mathematics | 20.0% | — | — |
| OTIS Mock AIME 2024–2025Competition mathematics | 81.1% (best) | 66.7% | 67.5% |
| SimpleQA VerifiedShort factual questions | 11.7% | 13.2% (best) | — |
| Price per million tokens | |||
| Input | $0.05 (best) | $1.00 | — |
| Output | $0.40 (best) | $5.00 | — |
| Cached input | $0.005 (best) | $0.10 | — |
| Blended (3:1) | $0.138 (best) | $2.00 | — |
| Long-context rate | Same rate | Same rate | — |
| Price source | Official OpenAI API | Official Anthropic API | — |
| Limits | |||
| Context window | 400,000 tokens | 200,000 tokens | 524,288 tokens (best) |
| Max output | 128,000 tokens | 64,000 tokens | 524,288 tokens (best) |
| Inputs and features | |||
| Text | Yes | Yes | Yes |
| Images | Yes | Yes | No |
| PDFs | No | Yes | No |
| Audio | No | No | No |
| Video | No | No | No |
| Reasoning | Yesminimal · low · medium · high | Yes | Yes |
| Tool calling | Yes | Yes | Yes |
| Structured output | Yes | Yes | No |
| Availability | |||
| Weights | Proprietary | Proprietary | OpenApache 2.0 |
| API model ID | gpt-5-nano | claude-haiku-4-5 | — |
| API providers | 30 | 48 (best) | — |
| Released | Aug 7, 2025 | Oct 15, 2025 | Aug 20, 2025 |
| Knowledge cutoff | May 30, 2024 | Feb 28, 2025 | Jul 2024 |
What would a month cost?
Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.
- GPT-5 Nano$1.30
- Claude Haiku 4.5$20.00
- Seed-OSS-36B-Instruct—
Which should you choose?
Which is better: GPT-5 Nano, Claude Haiku 4.5 or Seed-OSS-36B-Instruct?
GPT-5 Nano is the better all-round choice, scoring 70/100 against Claude Haiku 4.5 (66) and Seed-OSS-36B-Instruct (60). It leads on capability. Claude Haiku 4.5 wins on inputs & features. Seed-OSS-36B-Instruct wins on context window. The score weighs capability 67%, inputs & features 20%, context window 13%. Capability uses the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025), because Seed-OSS-36B-Instruct has no Capabilities Index score yet.
Which is cheaper, GPT-5 Nano, Claude Haiku 4.5 or Seed-OSS-36B-Instruct?
GPT-5 Nano is cheaper at $0.05 input / $0.40 output per million tokens (official OpenAI API price). Claude Haiku 4.5 costs $1.00 input / $5.00 output per million tokens (official Anthropic API price). At a typical mix of three input tokens to one output token, that is $0.138 per million tokens for GPT-5 Nano versus $2.00 for Claude Haiku 4.5 (15× as much). Seed-OSS-36B-Instruct has no published per-token price.
Which scores higher on benchmarks?
Not every model here has a Capabilities Index score, so we compare the average of shared benchmarks (GPQA Diamond and OTIS Mock AIME 2024–2025): GPT-5 Nano 75.3%, Seed-OSS-36B-Instruct 69.5% and Claude Haiku 4.5 68.9%. On individual benchmarks: GPQA Diamond — Seed-OSS-36B-Instruct 71.5%, Claude Haiku 4.5 71.2%, GPT-5 Nano 69.4%; OTIS Mock AIME 2024–2025 — GPT-5 Nano 81.1%, Seed-OSS-36B-Instruct 67.5%, Claude Haiku 4.5 66.7%.
Which is better for coding?
There are no published SWE-bench Verified results for GPT-5 Nano, Claude Haiku 4.5 and Seed-OSS-36B-Instruct yet, so there is no like-for-like coding score. On overall capability, GPT-5 Nano leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.
Which has the bigger context window?
Seed-OSS-36B-Instruct has the largest context window at 524,288 tokens, against 400,000 for GPT-5 Nano and 200,000 for Claude Haiku 4.5. Maximum output per response: GPT-5 Nano up to 128,000, Claude Haiku 4.5 up to 64,000, Seed-OSS-36B-Instruct up to 524,288 tokens.
Which can read images, PDFs, audio or video?
GPT-5 Nano accepts text and images; Claude Haiku 4.5 accepts text, images and PDFs; Seed-OSS-36B-Instruct accepts text. Claude Haiku 4.5 handles the widest range of inputs.
Are any of these open source?
Seed-OSS-36B-Instruct publishes its weights (Apache 2.0) and can be self-hosted; GPT-5 Nano and Claude Haiku 4.5 is proprietary.
Which is newer?
Claude Haiku 4.5 is the newest, released Oct 15, 2025. Seed-OSS-36B-Instruct came out Aug 20, 2025; GPT-5 Nano came out Aug 7, 2025. Knowledge cutoff: GPT-5 Nano May 30, 2024, Claude Haiku 4.5 Feb 28, 2025, Seed-OSS-36B-Instruct Jul 2024.
How do you decide the winner?
Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Nov 2, 2026.
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